=IFERROR(INDEX($A$2:$A$30,SMALL(IF(COUNTIF(INDIRECT("a2:a"&ROW($A$2:$A$30)),$A$2:$A$30)=1,ROW($A$2:$A$30),""),ROW(1:1))-1),"")按ctrl+shift+回车，使用组公式
